Yo mama's so fat that the National Weather Service names all of her farts.
Yo mama's so fat that when she ran out into the street and I tried swerving around her, I ran out of gas!
Yo mama's so old she has an autographed Bible.
Yo mama's so stupid she sold her car for gas money.
Yo mama's so ugly, we call Henry Ford our savior for inventing a way to escape her.
Yo mama's so fat that when God said "Let there be light", he told her to get the fuck out of the way!
Yo mama's so stupid that she yelled into an envelope to send a voicemail.
Yo mama's so ugly, when she looked out the window, she got arrested for mooning!
Yo mama's so fat, when she walks past the TV, you miss 3 episodes of the show!

Jokes that nobody actually means. People just try to see who's is better.

A retarded joke that middle and high schoolers say to each other that starts with "yo mama's so______that_______________." It's is used to be funny, but if you say it to the wrong person, they will beat the shit out of you.

Here's a nice one.........
Yo mama so stupid that she held a bonfire at a shell gas station.

a joke to tell when you're in a really trite mood and feel like laughing for no exact reason.

a joke made to insult a certain characteristic about some ones mum. this type of joke isn't usually used as a directed insult, but more so as an exchange of jokes between two friends.